U.S. patent application number 11/222086 was filed with the patent office on 2007-03-08 for pipeline inspection system.
This patent application is currently assigned to ULC Robotics, Inc.. Invention is credited to Hermann Herrlich, George Lohr, G. Gregory Penza.
Application Number | 20070051192 11/222086 |
Document ID | / |
Family ID | 37828832 |
Filed Date | 2007-03-08 |
United States Patent
Application |
20070051192 |
Kind Code |
A1 |
Penza; G. Gregory ; et
al. |
March 8, 2007 |
Pipeline inspection system
Abstract
An inspection system configured for "no-blow" use in a
pressurized gas pipeline includes a push rod wound around a spool
for convenient deployment and portability. A camera disposed on one
end of the push rod is configured to relay images back to a
monitor. A motor is configured for remote actuation by an operator,
and provides for self-propelled movement of the camera in the
pipeline. An entry tube is configured for sealed entry into the
pipeline to facilitate entry of the camera and push rod. A guide
shoe at the end of the entry tube provides a smooth transition-for
the camera and push rod as it leaves the entry tube and enters the
pipeline. An automatically deployable and retractable positioning
system is used to keep the camera away from an interior surface of
the pipeline, and in the case of smaller pipelines, centers the
camera within the pipeline.
Inventors: |
Penza; G. Gregory;
(Huntington, NY) ; Lohr; George; (Commack, NY)
; Herrlich; Hermann; (Lindenhurst, NY) |
Correspondence
Address: |
BROOKS KUSHMAN P.C.
1000 TOWN CENTER
TWENTY-SECOND FLOOR
SOUTHFIELD
MI
48075
US
|
Assignee: |
ULC Robotics, Inc.
160-B West Industry Court
Deer Park
NY
11729
|
Family ID: |
37828832 |
Appl. No.: |
11/222086 |
Filed: |
September 8, 2005 |
Current U.S.
Class: |
73/865.8 |
Current CPC
Class: |
G01N 21/88 20130101;
F16L 2101/30 20130101; F16L 55/30 20130101; F16K 7/10 20130101;
G01N 21/954 20130101; F16L 55/46 20130101; F16L 41/06 20130101;
F16L 55/26 20130101 |
Class at
Publication: |
073/865.8 |
International
Class: |
G01M 19/00 20060101
G01M019/00 |
Claims
1. An inspection system for inspecting a pressurized gas pipeline,
the inspection system comprising: an elongate flexible guide
member; a first conduit having first and second ends, the first
conduit being configured for sealed insertion into the pipeline
such that the first end is outside the pipeline, the second end is
inside the pipeline, and escape of gas from inside the pipeline is
inhibited as the second end is inserted into the pipeline, the
first conduit being further configured to receive the guide member
therein, thereby facilitating entry of the guide member into the
pipeline; a first seal cooperating with the first conduit and the
guide member to inhibit gas from the pipeline from escaping through
an inside of the first conduit; a transition member adjacent the
second end of the first conduit for facilitating a change in
direction of the guide member as the guide member enters the
pipeline from within the first conduit; and a camera attached to
the guide member and configured to pass through the first conduit
and into the pipeline.
2. The inspection system of claim 1, further comprising: a second
conduit configured for sealed attachment to the pipeline at an
opening in the pipeline, and further configured to receive the
first conduit therein, thereby facilitating entry of the first
conduit into the pipeline through the opening; and a second seal
cooperating with the first and second conduits for effecting the
sealed insertion of the first conduit into the pipeline.
3. The inspection system of claim 1, wherein at least a portion of
the first conduit has a generally round cross section defining an
outer diameter, thereby allowing the first conduit to be inserted
through a generally round entry hole in the pipeline, and wherein
the transition member is attached to the first conduit and
configured to not extend beyond the outer diameter of the first
conduit, thereby allowing the first conduit to be inserted into the
pipeline through the entry hole without interference from the
transition member.
4. The inspection system of claim 3, wherein the first conduit
includes an open channel proximate the second end, the transition
member forming one end of the channel.
5. The inspection system of claim 1, wherein the transition member
has a first surface and a second surface generally opposite the
first surface, the first surface being configured to provide a
contact surface for the camera as the camera leaves the first
conduit and enters the pipeline, at least a portion of the second
surface being generally convex, thereby increasing contact between
the second surface and a generally concave interior surface of the
pipeline.
6. The inspection system of claim 1, the pipeline defining a first
longitudinal axis, and wherein the first conduit defines a second
longitudinal axis, and the first conduit is configured for
insertion into the pipeline such that the first and second
longitudinal axes form an oblique angle with each other, thereby
further facilitating entry of the guide member into the
pipeline.
7. The inspection system of claim 1, further comprising a motor
operable to move the guide member through the first conduit and
into the pipeline, the motor being disposed proximate the first end
of the first conduit to facilitate remote feeding of the guide
member through the first conduit.
8. The inspection system of claim 1, further comprising an
automatically deploying and retracting positioning system disposed
between the camera and one end of the guide member for positioning
the camera away form an inner surface of the pipeline.
9. The inspection system of claim 8, wherein the positioning system
includes: a plurality of flexible arms, each of the arms being
deployable in a direction away from the camera toward the inner
surface of the pipeline, and a biasing member configured to exert a
force on one end of each of the arms, thereby facilitating the
automatic deployment of the arms.
10. The inspection system of claim 9, wherein one end of each of
the arms is pivotally attached to the biasing member adjacent one
end of the biasing member, thereby facilitating axial movement of
the one end of the biasing member when an inward force is applied
to the arms.
11. The inspection system of claim 1, further comprising: a reel
for dispensing and retracting the guide member; and a monitor in
communication with the camera and attached to the reel for remotely
providing images captured by the camera.
12. An inspection system for a pressurized pipeline having an
interior with a first diameter, the inspection system comprising:
an elongate flexible guide member having a first end configured for
entry into the pipeline; an entry tube configured for insertion
into the pipeline, thereby providing access to the interior of the
pipeline for the guide member; a camera having first and second
ends and disposed adjacent the first end of the guide member, the
camera being configured to pass through the entry tube and into the
pipeline; a biasing member disposed between the first end of the
guide member and the camera, the biasing member having a first end
axially fixed relative to the first end of the guide member, and a
second end axially movable relative to the first end of the guide
member; and at least two flexible arms, each of the arms having a
first end pivotally disposed proximate one of the ends of the
camera, and a second end pivotally disposed proximate the second
end of the biasing member, thereby facilitating automatic outward
movement of a portion of each of the arms as the second end of the
biasing member moves away from the first end of the biasing member
when the arms exit the entry tube into the pipeline interior, and
further facilitating inward movement of a portion of each of the
arms when the arms are retracted into the entry tube, thereby
causing a movement of the second end of the biasing member toward
the first end of the biasing member.
13. The inspection system of claim 12, further comprising a support
member disposed between the first end of the guide member and the
first end of the camera for supporting the camera remotely from the
first end of the guide member, thereby providing a distance between
the first end of the guide member and the camera to facilitate use
of the flexible arms.
14. The inspection system of claim 12, further comprising an
adapter member configured for attachment to the first end of the
guide member, and further configured to receive the first end of
the biasing member, thereby axially fixing the first end of the
biasing member relative to the first end of the guide member.
15. The inspection system of claim 12, wherein the biasing member
includes a coil spring, and the second end of each of the arms
includes an aperture therethrough, and wherein the coil spring is
disposed through each of the apertures, thereby forming the pivotal
attachments between the biasing member and each of the arms.
16. The inspection system of claim 12, further comprising a guide
shoe disposed proximate one end of the entry tube for deflecting
the guide member from an orientation generally parallel to the
entry tube to an orientation generally parallel to the
pipeline.
17. An inspection system for a pressurized pipeline which defines a
first longitudinal axis, the inspection system comprising: an
elongate flexible guide member; a first conduit having first and
second ends and defining a second longitudinal axis, the first
conduit being configured for insertion into the pipeline, and
further configured to receive the guide member therein to
facilitate entry of the guide member into the pipeline; a camera
attached to the guide member and configured to pass through the
first conduit and into the pipeline; a motor arrangement disposed
proximate the first end of the first conduit and operable to move
the guide member through the first conduit and into the pipeline;
and a transition member adjacent the second end of the first
conduit and having a first surface forming an oblique angle with
the first longitudinal axis and further forming an oblique angle
with the second longitudinal axis, the first surface facilitating a
change in direction of the guide member as the camera contacts the
first surface of the transition member.
18. The inspection system of claim 17, wherein the motor
arrangement includes a motor and a pair of wheels driven by the
motor and configured to capture the guide member therebetween,
thereby pushing the guide member through the first conduit and into
the pipeline.
19. The inspection system of claim 16, the pressurized pipeline
being selectively accessible through a valve system, the inspection
system further comprising a second conduit having first and second
ends and configured to receive the first conduit therein, the first
end of the second conduit being configured for attachment to the
pipeline valve system, thereby facilitating entry of the first
conduit into the pipeline through the valve system.
20. The inspection system of claim 19, further comprising a
retaining structure disposed proximate the second end of the second
conduit, the retaining structure being configured to secure the
first conduit relative to the second conduit after the first
conduit is moved through the second conduit and into the pipeline.
Description
BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a pipeline inspection
system.
[0003] 2. Background Art
[0004] For more than 30 years, video inspection has been a baseline
fundamental analytical tool for the evaluation and assessment of
pipeline integrity. Originally developed as an aid for sewer system
maintenance, video inspection equipment and techniques have played
a key role in the development of "no-dig" and "trenchless" pipeline
rehabilitation methods. This is because the choice of the best
trenchless rehabilitation method, for any given application, is
often largely based on the video inspection that takes place prior
to the rehabilitation. Thus, the information gleaned from the
pre-rehabilitation video inspection is used as the basis for key
decisions that drive the entire rehabilitation process.
[0005] The inspection of pipes often falls into two broad
categories: inspections performed for purposes of preventative
maintenance, and inspections performed as a response to a need for
repair maintenance. The former category may include such things as
locating cracks in the pipeline prior to their reaching a critical
length, discovering the location of unknown branches or service
tees, determining the exact location of valves and fittings, and
finding water within the pipeline. In general, video inspection
equipment is useful as a proactive tool for assessing the
cleanliness, corrosion, and structural integrity of the pipeline.
In the case of repair maintenance, high quality video inspection
data is also very important. Indeed, the very nature of repair
maintenance is such that it may include responding to emergency
situations, particularly where hazardous materials are involved.
Thus, the importance of quality video inspection equipment and
techniques is further underscored.
[0006] One attempt to provide a pipe inspection system that can be
used in a gas pipeline is described in U.S. Pat. No. 5,195,392
(Moore et al.). Moore et al. describes an inspection system for a
pipeline that utilizes a camera head at the end of a snake which is
fed down the pipeline to capture images at a desired location. The
inspection system of Moore et al. requires two operators: one to
feed the snake and camera head down the pipeline, and a second to
view the images captured by the camera and provide instructions to
the operator moving the camera. The snake is wound around a drum,
and uncoiled by the first operator as the camera is manually fed
down the pipeline. Moore et al. does note that some commercially
available snakes may have electrically powered drum rotation. The
camera may be provided with a number of centralizing members which
are used to keep the camera approximately centered within the
cross-section of the pipeline. After the camera is inserted in the
pipeline, a curved tube can be positioned about the snake within
the pipeline, and clamped in place.
[0007] One limitation of the pipeline inspection system described
in Moore et al. is that it requires two operators to perform the
inspection task. The first is required to feed the snake and camera
down the pipeline, while the second is required to view the images
from the camera and direct positioning of the camera by the first
operator. In addition, the first operator is required to remain in
close proximity to the opening of the pipeline, which may be
undesirable if the pipeline is carrying pressurized gas. Although
Moore et al. does contemplate the use of a motorized snake drum, an
operator is still required to feed the snake down the pipeline
under the direction of the second operator. Another limitation of
the inspection system described in Moore et al. is that the camera
must be placed through an opening in the pipeline prior to the
opening being sealed by placement of the curved tube and its
associated gasket. Thus, the opening to the pipeline remains
unsealed until the camera head and a portion of the snake are
inserted. This may be particularly undesirable when inspecting a
high-pressure gas pipeline.
[0008] Therefore, a need exists for an inspection system that can
be used to inspect a high-pressure gas pipeline, and that can be
installed under sealed conditions so that seals are in place before
the inspection apparatus is inserted into the pipeline. It would
also be desirable to have a pipeline inspection system that would
allow a single operator to control a camera from a location away
from the pipeline opening, particularly where the pipeline is a
high-pressure gas pipeline. In addition, it would also be desirable
to have a pipeline inspection system with a camera having a
positioning system which automatically deploys and retracts upon
insertion and retraction of the camera, without the need for manual
manipulation of the positioning system by an operator.
SUMMARY OF THE INVENTION
[0009] The present invention provides a pipeline inspection system
which can used by a single operator, and can be used in a
high-pressure gas pipeline and installed under sealed conditions to
inhibit the escape of gas from inside the pipeline. At least one
embodiment of the present invention includes an entry tube
configured for insertion into the pipeline prior to insertion of a
camera and push rod. The invention also provides a positioning
system for the camera which is automatically deployable as it exits
the entry tube and enters the pipeline. Further, the positioning
system is automatically retractable as it is removed from the
pipeline and enters the entry tube.
[0010] The invention further provides an inspection system for
inspecting a pressurized gas pipeline that includes an elongate
flexible guide member and a first conduit having first and second
ends. The conduit is configured for sealed insertion into the
pipeline such that the first end is outside the pipeline, the
second end is inside the pipeline, and escape of gas from inside
the pipeline is inhibited as the second end is inserted into the
pipeline. The first conduit is further configured to receive the
guide member therein, which facilitates entry of the guide member
into the pipeline. A first seal cooperates with the first conduit
and the guide member to inhibit gas from the pipeline from escaping
through an inside of the first conduit. A transition member is
located adjacent to the second end of the conduit for facilitating
a change in direction of the guide member as the guide member
enters the pipeline from within the conduit. A camera is attached
to the guide member, and it is configured to pass through the
conduit and into the pipeline.
[0011] The invention also provides an inspection system for a
pressurized pipeline having an interior with a first diameter. The
inspection system includes an elongate flexible guide member having
a first end configured for entry into the pipeline. An entry tube
is configured for insertion into the pipeline, thereby providing
access to the interior of the pipeline for the guide member. A
camera has first and second ends, and is disposed adjacent the
first end of the guide member. The camera is configured to pass
through the entry tube and into the pipeline. A biasing member is
disposed between the first end of the guide member and the camera.
The biasing member has a first end axially fixed relative to the
first end of the guide member. The biasing member also has a second
end axially movable relative to the first end of the guide member.
The inspection system also includes at least two flexible arms,
each of which has a first end pivotally disposed proximate to one
of the ends of the camera. Each of the arms also has a second end
pivotally disposed proximate to the second end of the biasing
member. This facilitates automatic outward movement of a portion of
each of the arms as the second end of the biasing member moves away
from the first end of the biasing member when the arms exit the
entry tube into the pipeline interior. This also facilitates inward
movement of a portion of each of the arms when the arms are
retracted into the entry tube, thereby causing a movement of the
second end of the biasing member toward the first end of the
biasing member.
[0012] The invention further provides an inspection system for a
pressurized pipeline which defines a first longitudinal axis. The
inspection system includes an elongate flexible guide member, and a
first conduit having first and second ends and defining a second
longitudinal axis. The first conduit is configured for insertion
into the pipeline, and further configured to receive the guide
member therein to facilitate entry of the guide member into the
pipeline. A camera is attached to the guide member and configured
to pass through the first conduit into the pipeline. A motor
arrangement is disposed proximate the first end of the conduit, and
is operable to move the guide member through the first conduit and
into the pipeline. A transition member is located adjacent the
second end of the first conduit, and has a first surface forming an
oblique angle with the first longitudinal axis, and further forming
an oblique angle with the second longitudinal axis. The first
surface facilitates a change in direction of the guide member as
the camera contacts the first surface of the transition member.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a partial schematic perspective view of one
embodiment of an inspection system in accordance with the present
invention;
[0014] FIG. 2 is a partial fragmentary view of a portion of the
inspection system shown in FIG. 1;
[0015] FIG. 3 is a fragmentary view of a portion of an entry tube
and guide shoe for the inspection system shown in FIG. 1;
[0016] FIG. 4 is a partial fragmentary view of a portion of the
guide system shown in FIG. 1, including a positioning system
deployed within a pipeline;
[0017] FIG. 5 is a front plan view of the pipeline and positioning
system shown in FIG. 4; and
[0018] FIG. 6 is a side plan view showing details of an adapter
member shown in FIG. 4.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT(S)
[0019] FIG. 1 shows a partially schematic perspective view of a
pipeline inspection system 10 in accordance with one embodiment of
the present invention. The inspection system 10 includes a camera
12 which is attached to an elongate flexible guide member, or push
rod 14. The push rod 14 is wound around a spool 16, which has a
video display monitor 18 conveniently attached thereto. The monitor
18 is electrically connected to the camera 12, for providing images
from inside a pipeline 20. As explained in detail below, a
positioning system 22 is disposed between the camera 12 and the
push rod 14 for positioning the camera 12 within a pipeline, such
as the pipeline 20.
[0020] The pipeline 20 may be a high-pressure gas pipeline, for
example, containing gas at 60 pounds per square inch (psi). To
facilitate entry into the pipeline 20, a valve system 24 is used to
provide selective access to an opening 25 in the pipeline 20. Any
valve system that provides access to an interior 26 of the pipeline
20 through the opening 25 may be used. One example of such a valve
system is the valve system commercially available from ALH Systems
Limited. As an alternative, a fitting made from polyethylene, or
another polymeric material or materials, could be attached to the
pipeline 20, for example, by electrofusion. Other fittings could
also be used, for example, a metal nipple could be welded to the
pipeline.
[0021] Once a fitting is attached to the pipeline 20, a drill (not
shown) having a sealed attachment to the fitting, could be used to
create the opening 25. The inspection system 10 also includes a
first conduit, or entry tube 28, which facilitates entry of the
camera 12 and push rod 14 into the pipeline 20. A second conduit 30
has a first end 32 which is configured for attachment to the valve
system 24. As shown in FIG. 2, the second conduit 30 is attached to
the pipeline 20 through the valve system 24. The second conduit 30
also has a second end 34 having a retaining structure, or clamp
arrangement 36, attached thereto. The clamp arrangement 36 allows
the entry tube 28 to be moved up and down to accommodate different
pipeline diameters. Once the entry tube is properly positioned, the
clamp arrangement 36 secures the entry tube 28 in place while the
pipeline 20 is inspected.
[0022] The inspection system 10 is configured for "no-blow" use on
pressurized pipelines, such as the pipeline 20. This means that the
inspection system 10 is configured to reduce to a minimum, or
completely eliminate, the escape of gas from a pipeline on which it
is being used. The entry tube 28 has a first end 38 which has a cap
40 attached thereto. The cap 40 contains a first seal, or packing
gland 35. The packing gland 35 cooperates with the entry tube 28
and the push rod 14 to provide a seal around the push rod 14 when
it is inserted into the pipeline 20. The packing gland 35 inhibits
gas from the pipeline 20 from escaping through the inside 37 of the
entry tube 28. In addition, a second seal, made up of three O-rings
39, cooperates with the entry tube 28 and the second conduit 30 to
provide sealed insertion of the entry tube 28 into the pipeline 20.
Although the seals 35, 39 are shown as a packing gland and O-rings,
respectively, it is understood that the use of different types of
sealing structures is contemplated by the present invention.
Moreover, although the packing gland 35 and the O-rings 39 are
configured to inhibit the escape of gas from the pipeline 20, it is
understood that some trace amounts of gas from the pipeline 20 may
enter the ambient environment.
[0023] In order to move the camera 12 up and down the pipeline 20,
a motor arrangement 41 is provided. The motor arrangement 41
includes a motor 42, which is connected to a gearbox 44. As
explained more fully below, the gearbox 44 contains a number of
rollers for facilitating movement of the push rod 14 into and out
of the pipeline 20. As shown in FIG. 1, the motor arrangement 41 is
attached directly to the entry tube 28; this assembly provides a
number of advantages. First, there is no need for a separate
support structure for the motor arrangement 41; rather, it is
attached to existing portions of the inspection system 10. In
addition, having the motor arrangement 41 in close proximity to the
first end of the entry tube 28, allows the push rod 14 to be moved
forward and backward in the pipeline 20 without the need for an
operator to feed the push rod 14 at the point of entry. Thus, an
operator may actuate the motor 42 remotely, which provides a number
of advantages over existing inspection systems. First, use of the
motor arrangement 41 allows a single operator to effectively use
the inspection system 10. Secondly, the operator can actuate the
motor 42 from a safe distance away from the opening in the pipeline
20. In addition, the use of the motor arrangement 41 provides for
controlled, precise movement of the camera 12 up and down the
pipeline 20, thereby increasing the accuracy of the inspection and
the ease with which it is carried out.
[0024] The gearbox 44 includes openings 46, 48 which allow the push
rod 14 to pass therethrough. Also shown in FIG. 1 are handles 50,
52 attached to the entry tube 28. The handles 50, 52 allow the
operator to adjust the entry tube 28 up and down based on the
diameter of the pipeline being inspected. The motor arrangement 41
is attached to the entry tube 28 via a clamp arrangement 54, which
allows the motor arrangement 41 to be completely removed from the
entry tube 28. This helps to facilitate positioning of the entry
tube 28 within a pipeline, such as the pipeline 20. The operator
merely loosens the clamp arrangement 36, adjusts the height of the
entry tube 28 using the handles 50, 52, and then secures the
position of the entry tube 28 by locking the clamp arrangement
36.
[0025] FIG. 2 shows a partial fragmentary side view of a portion of
the inspection system 10. As shown in FIG. 2, the gearbox 44
includes first and second halves 56, 58 which are held together
with fastening arrangements 60, 62. Having the gearbox 44 split in
this manner facilitates set up of the inspection system 10. For
example, to insert the camera 12 into the pipeline 20, the cap 40
on the entry tube 28 is loosened to allow the camera 12 and the
positioning system 22 to pass through the packing gland under the
cap 40 and into the entry tube 28. This may conveniently take place
prior to the motor arrangement 41 being attached to the entry tube
28.
[0026] Prior to the motor arrangement 41 being attached to the
entry tube 28, the first and second halves 56, 58 can be opened by
loosening nuts 64, 66 on the fastening arrangements 60, 62. This
allows eye bolts 68, 70 to be pivoted to allow the first and second
halves 56, 58 of the gearbox 44 to be swung open on a hinge (not
shown). The push rod 14 can then be placed between pairs of rollers
72, 74; 76, 78; and 80, 82. The motor 42 can be configured with a
gear or gears to drive at least one of the rollers, such as the
roller 74 shown in FIG. 2. In this way, the rollers 72-82 may be
driving members, or they may merely act as guides, depending on the
particular arrangement within the gearbox 44. As shown in FIG. 2, a
second end 84 of the second conduit 30 is configured for attachment
to the valve system 24. In the embodiment shown in FIG. 2, the
second conduit 30 is welded to a plate 86 which cooperates with the
valve system 24 to ensure that a seal is maintained even in the
presence of high-pressure gas within the pipeline 20.
[0027] Also shown in FIG. 2, the entry tube 28 includes a second
end 88 and a transition member, or guide shoe 90, disposed
proximate to the second end 88. The guide shoe 90 facilitates a
change in direction of the push rod 14 as it enters the pipeline 20
from within the entry tube 28. As shown in FIG. 2, the entry tube
28 has a generally round cross-section, having a diameter (D). The
guide shoe 90 is configured so that it does not extend beyond the
outer diameter (D) of the entry tube 28, which allows the entry
tube 28 to be inserted through a relatively small hole in the
pipeline 20, without interference from the guide shoe 90. In order
to facilitate entry of the camera 12, the entry tube 28 includes an
open channel 92 proximate to its second end 88. As shown in FIG. 2,
the guide shoe 90 forms one end of the channel 92.
[0028] FIG. 3 shows a portion of the entry tube 28, and in
particular a portion near the second end 88. As shown in FIG. 3,
the guide shoe 90 has a first surface 94 and a second surface 96
generally opposite the first surface 94. The second surface 96 is
generally convex, which helps to increase the contact between the
second surface 96 and a generally concave interior surface 98 of
the pipeline 20 (see FIG. 2). As shown in FIG. 2, the first surface
94 of the guide shoe 90 forms an oblique angle with a first
longitudinal axis 100 of the pipeline 20. It also forms an oblique
angle with a second longitudinal axis 102 of the entry tube 28.
[0029] In the embodiment shown in FIG. 2, the first and second
longitudinal axes 100, 102 form an oblique angle with each other.
For example, if the pipeline 20, and therefore its longitudinal
axis 100, is generally horizontal, then the entry tube 28, and its
longitudinal axis 102, are not oriented vertically. Rather, the
entry tube 28 is provided with an angle of approximately 20.degree.
away from vertical, which helps to facilitate entry of the camera
12 and push rod 14 into the pipeline 20.
[0030] The present invention does, however, contemplate orienting
an entry tube, such as the entry tube 28, vertically to a
horizontal pipeline. This may be convenient when a method such as
keyholing is used to access the pipeline. Keyholing attempts to
minimize the concrete and/or soil removal required to access the
pipeline; therefore, the access hole diameter is relatively small.
When keyholing is used, it may not be practical to orient an entry
tube, such as the entry tube 28, at an angle away from vertical. In
such a case, the present invention can be configured with an entry
tube whose longitudinal axis is 90.degree. from the longitudinal
axis of the pipeline it is entering. This is possible, in part,
because of the use of a guide shoe, such as the guide shoe 90. Even
if the entry tube 28 were oriented such that the axis 102 was
90.degree. from the axis 100, the guide shoe 90 would provide a
smooth transition for the camera 12 and push rod 14 from its
initial orientation parallel to the entry tube 28, to its later
orientation generally parallel to the pipeline 20.
[0031] As shown in FIG. 2, the pipeline 20 is large enough that the
positioning system 22 does not contact the top and bottom of the
interior surface 98. Rather, in such a large pipeline, such as the
pipeline 20, the positioning system 22 merely keeps the camera 12
from dragging along the bottom of the interior surface 98. FIG. 4
shows an example of the camera 12 and the positioning system 22
inside a pipeline 104 having a smaller diameter than the pipeline
20 shown in FIG. 2. As shown in FIG. 4, the positioning system 22
keeps the camera 12 generally centered within the interior of the
pipeline 104. The positioning system 22 includes a plurality of
flexible arms 106, 108. Although it is possible to configure a
positioning system, such as the positioning system 22, with only
two flexible arms, the positioning system 22, in fact, has three
flexible arms 106, 108, 110 (see FIG. 5).
[0032] As discussed above, the positioning system 22 is
automatically deployable as it exits the entry tube 28 into a
pipeline, and is automatically retractable as it leaves the
pipeline and returns to the entry tube 28. The automatic deployment
and retraction of the positioning system 22 is particularly
beneficial in applications involving high-pressure gas pipelines,
where it is desirable to have little or no interaction between an
operator and an open pipeline. As shown in FIG. 4, each of the arms
106, 108 (and the arm 110 not visible in FIG. 4) has pivotal
attachments 112, 114 at a first end 116 of the camera 12. Each of
the arms 106, 108 (and 110) also has pivotal attachments 118, 120
at a biasing member 122. In the embodiment shown in FIG. 4, the
biasing member 122 is a coil spring which is disposed adjacent a
first end 124 of the push rod 14. The spring 122 has a first end
126 axially fixed relative to the first end 124 of the push rod 14.
In particular, the first end 126 is axially fixed by an adapter
member 128 which is attached to the first end 124 of the push rod
14.
[0033] FIG. 6 shows a side view of the adapter 128, including two
threaded apertures 130, 132. The adapter 128 may be made in two
halves, such that the first end 124 of the push rod 14 can be
inserted into an opening 134 between the two halves of the adapter
128, and threaded fasteners (not shown) can be used to tighten the
two halves of the adapter 128 to secure the push rod 14
therebetween. Also shown in FIG. 6, the adapter 128 includes a
second opening 136 which is configured to receive one end of a
support member 138 (see FIG. 4). As with the first end 124 of the
push rod 14, the adapter 128 can be clamped down on the support
member 138 after the spring 122 is installed on the outside surface
140 of the adapter 128. Returning to FIG. 4, it is shown that the
support member 138 is disposed between the first end 124 of the
push rod 14 and the first end 116 of the camera 12. The support
member 138 supports the camera 12 remotely from the first end 124
of the push rod 14, and thereby provides a distance between them to
facilitate use of the positioning system 22.
[0034] As noted above, the spring 122 has a first end 126 that is
axially fixed relative to the first end 124 of the push rod 14.
Conversely, a second end 142 of the spring 122 is axially movable
relative to the first end 124 of the push rod 14. As shown in FIG.
4, the pivotal attachments 118, 120 include apertures 144, 146
through the flexible arms 106, 108. Each of the apertures 144, 146
has a coil 148 of the spring 122 disposed therethrough. The coil
148 is near the movable end 142 of the spring 122. This facilitates
the automatic deployment and retraction of the positioning system
22.
[0035] In particular, as the camera 12 and positioning system 22
leave the relatively small diameter of the entry tube 28 and enter
the pipeline 104, the second end 142 of the spring 122 moves away
from the first end 126 of the spring 122. This facilitates an
automatic outward movement of the arms 106, 108 (and 110) toward an
interior surface 150 of the pipeline 104. Similarly, when the
positioning system 22 is retracted into the smaller diameter entry
tube 28, an inward force is exerted on the arms 106, 108, 110 which
forces the second end 142 of the spring 122 closer to the first end
126 of the spring 122. This means that the positioning system 22
can be automatically deployed from the smaller diameter entry tube
28 into a larger diameter pipeline, such as the pipeline 104,
without any interaction from a system operator. Similarly, no
action is required to retract the positioning system 22, other than
the retraction of the push rod 14 back into the entry tube 28.
[0036] While embodiments of the invention have been illustrated and
described, it is not intended that these embodiments illustrate and
describe all possible forms of the invention. Rather, the words
used in the specification are words of description rather than
limitation, and it is understood that various changes may be made
without departing from the spirit and scope of the invention.
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